Have you read 1984 yet? It’s a work of fiction, but very insightful.

I use a ConnectPRO UD-14+KIT, 4-Port DVI+USB DDM KVM Switch:

https://connectpro.com/products/ud-14-dvi-d-kvm-switch-for-one-monitor-and-four-computers

It supports four machines, but I use it with either 2 or 3. It works well, I have no complaints

It’s possible to have only one earphone working if the connector is not pushed all the way into the jack.